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docs/wavetables.md

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+# Wavetables
+
+Control wavetable synthesis parameters for scanning through waveforms.
+
+## Scan Position
+
+The `scan` parameter controls which waveform in the wavetable is active:
+
+```forth
+"wt" s 0.0 scan .   ( first waveform )
+"wt" s 0.5 scan .   ( middle of table )
+"wt" s 1.0 scan .   ( last waveform )
+```
+
+## Wavetable Length
+
+Set the cycle length in samples:
+
+```forth
+"wt" s 2048 wtlen .  ( standard wavetable size )
+```
+
+## Scan Modulation
+
+Animate the scan position with an LFO:
+
+```forth
+"wt" s 0.2 scanlfo .    ( LFO rate in Hz )
+"wt" s 0.4 scandepth .  ( LFO depth 0-1 )
+"wt" s "tri" scanshape . ( LFO shape )
+```
+
+Available shapes: `sine`, `tri`, `saw`, `square`, `sh` (sample & hold)
+
+## Example
+
+```forth
+"wavetable" s
+  60 note
+  0.25 scan
+  0.1 scanlfo
+  0.3 scandepth
+  "sine" scanshape
+.
+```
+
+## Words
+
+| Word | Stack | Description |
+|------|-------|-------------|
+| `scan` | (f --) | Set wavetable scan position (0-1) |
+| `wtlen` | (n --) | Set wavetable cycle length in samples |
+| `scanlfo` | (f --) | Set scan LFO rate (Hz) |
+| `scandepth` | (f --) | Set scan LFO depth (0-1) |
+| `scanshape` | (s --) | Set scan LFO shape |